Animal traps typically used for rodents are available using a variety of methods to capture or kill the rodent but can be generally classified into two groups, traps with powerful springs that attempt to kill the animal such as the familiar spring trap, and traps that capture the animal alive within an enclosure.
Spring traps such as those shown in U.S. Pat. No. 1,791,172 to Suhr, while generally effective provided the spring is strong enough, often mutilate the animal and do not contain the animal such that the trap may be dragged several feet leaving a trail of blood and feces. While this type of trap is inexpensive offering the option to dispose of the trap, the traps can catch fingers while trying to set, are messy, are unsanitary to remove the rodent from the trap, and occasionally allow careful enough rodents to steal the bait without being caught. While improvements have been made to the simple spring trap such as those disclosed in U.S. Pat. No. 4,369,595 to Kness where a bar was added to reduce the risk of catching fingers while setting the trap and reduce the mess related to releasing the animal from the trap, where the bait receptacle was moved off the trigger to eliminate trigger sensitivity change due weight of the bait, and where a larger trigger was added to reduce the risk of the animal stealing the bait, the spring trap still occasionally mutilates the animal, is unsanitary due to the blood and feces left around the trap, and can still easily trap fingers.
Traps that capture the animal alive within an enclosure can be can be sub divided into two smaller groups, multi-catch and single-catch live traps. While the multi-catch traps offer the ability to catch several rodents, they also have problems such as one animal escaping when another animal enters the trap, or problems such as one animal eating part of another animal leaving a decaying smelly carcass to rot in the trap.
Single-catch live traps do not have the same problems associated multi-catch traps such as one rodent releasing or eating another rodent, and generally do not have the problems such as mutilated animals, traps being dragged away, or fingers being caught in powerful springs like the problems associated with the spring trap type of animal trap. Single-catch traps do however have different set of problems such as higher cost (making them undesirable to dispose of), sensitive trigger and balance mechanisms, false tripping due to the animal tripping the trap from the outside, and traps opening when the trap is moved or disposed of allowing the animal to escape.
To reduce cost, single-catch live traps have been designed with as little as two component parts such as the traps shown in U.S. Pat. No, 4,550,523 to Spiller and U.S. Pat. No. 4,787,170 to Kingsbury. The patent to Spiller discloses a trap consisting of an enclosure with a fulcrum approximately mid-length, and a door that closes when the enclosure tips. The patent to Kingsbury shows a trap consisting of an enclosure and a door held closed by gravity requiring the animal push under the door to enter the trap. While these two component part type traps are inexpensive, the tilting type trap as disclosed by Spiller is often tripped when the animal climbs on the outside causing the trap to trip without the animal inside. This type of trap is also sensitive to the amount of bait inside the trap, and may allow the animal to escape if the door is bumped or if the trap is disposed of and not positioned right-side-up in the garbage. The type of trap shown by Kingsbury does not allow the animal to trip the trap from the outside, but is less desirable since it requires the animal push a door open to enter the trap which often keeps the animal from entering the trap in the first place. This type of trap also requires the trap be made from a clear material to visually detect the condition of the trap (empty or full) which is undesirable to some people, and may also allow the animal to escape if the door is bumped or if the trap is disposed of and not positioned right-side-up in the garbage.
Although more than two component parts are involved, traps such as the one shown in U.S. Pat. No. 6,564,501 to Schislyonok involving a design similar to Spiller but provided with a lock to keep the door closed, are often tripped when the animal climbs on the outside, are sensitive to the amount of bait inside the trap, and require the trap remain right-side-up and on the surface the trap was placed to ensure the lock functions correctly as stated in the body of Schislyonok's patent. Bumping the latch once the trap is picked up, or disposing of the trap by throwing it in the garbage and not leaving the trap's latch against a flat surface where the animal's weight keeps the latch secured may allow the latch to become disengaged allowing the animal to escape.